Compositions and methods for providing coatings; materials; application techniques; and, resulting coated substrates

ABSTRACT

Techniques and compositions for applying films to a variety of substrates, from water-borne coating compositions, are provided. The techniques involve providing desiccant and applying the desiccant with water-borne film-forming composition, in application to a substrate. The desiccant composition provides for take up of free water in of the film-forming composition, without total reliance on ambient conditions, to advantage. Compositions, methods, techniques and resulting constructions are described. The techniques can be applied in wet thick film applications, but are not limited to such applications.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation of U.S. Ser. No. 13/905,407,filed May 30, 2013, which issued as U.S. Pat. No. 9,150,737 and includesthe disclosure of, with edits and additions, U.S. provisional61/654,293, filed Jun. 1, 2012. The complete disclosure of U.S. Ser. No.61/654,293 is incorporated herein by reference.

U.S. Ser. No. 13/905,407 was a continuation-in-part of U.S. Ser. No.13/314,377, filed Dec. 8, 2011, which claimed priority to provisionalapplication 61/421,730, filed Dec. 10, 2010. The complete disclosures ofU.S. Ser. No. 13/314,377 and U.S. provisional 61/421,730 areincorporated herein by reference.

Claims of priority are made to each of U.S. Ser. No. 13/905,407; U.S.provisional 61/654,293; U.S. Ser. No. 13/314,377 and U.S. Ser. No.61/421,730, to the extent appropriate.

FIELD OF THE DISCLOSURE

The present application relates to polymeric coating compositions andtechniques applicable to provide coatings on substrates. In particular,the present invention relates to coatings that are applied aswater-borne compositions, e.g. as latex-based compositions or sols. Thetechniques relate to providing drying agents or desiccants in filmsformed from such compositions in an advantageous manner, to facilitatecoating application, formation and characteristics.

BACKGROUND OF THE DISCLOSURE

Polymeric coatings are applied as liquids to a wide variety ofsubstrates. The coatings can be applied for a variety of reasons, forexample, as protective coatings, decorative coatings, sealants, forinsulation properties and/or to modify surface characteristics of thesubstrate to the surface characteristics of the coating.

In general terms, coatings applied as liquids comprise three primarycomponents: pigment; binder; and, solvent. In this context, the term“pigment” is used to refer to non-film forming components. The term“binder” is used to refer to those materials that form the film, i.e.solid materials that provide the protective and/or functional coating.The third component (solvent) is a fugitive material that functions as adispersing medium for the pigment and binder solids, and is a carrierfor transporting the solid materials to the substrate. Once the coatinghas been applied, it is generally desirable to rid the applied coatingof its carrier solvent as quickly as possible. For many coatings, theremoval and carrier solvent trigger some form of film forming processand involves the evaporation of the solvent to the atmosphere. When thecarrier solvents are organic in nature, they generally contribute toenvironmental problems (i.e. VOC levels and issues with VOCregulations). Of course when water is used as a solvent, VOC problemsare reduced.

In the construction industry, protective and/or decorative coatings areapplied to foundations, walls, roofs and various structures. Thematerials or substrates involved can comprise a variety of materials,for example masonry, cement, concrete, wood, fiber board, plaster,plaster board, metal, brick, paper, plastic, rubber, glass, asphaltand/or foam (e.g. styrene foam or polyurethane foam). The substratebeing coated may comprise portions of more than one type of material.Some of the substrates can be quite irregular or porous, and thusdifficult to coat. The substrates may be horizontal, vertical or of avariety of alternate configurations, or of complex shape and/ororientation.

Different issues may be presented, depending on the location and purposeof the substrate. For example, below grade structures (below groundlevel walls) often are subject to hydrostatic pressures fromgroundwater. The type of compositions applied as coatings to suchstructures may be intended, therefore, to provide both a good waterbarrier and a good vapor tight barrier.

Above grade exterior structures (for example above ground level exteriorwalls) are subject to weather and weathering effects, but it may also bedesirable that they be configured to “breathe”, i.e. allow passage ofwater vapor therethrough, to allow internal wall regions to dry.

Issues with formulation and application of protective coatings to a widevariety of substrates concern such variable factors as: environmentalconditions during application; drying time issues; coating thicknessissues; application conditions; and, logistical issues. Environmentalconditions, for example, can relate to whether the coating is applied inan internal closed environment, or an external, outside, openenvironment. Coating thickness issues can relate to how thick thecoating application needs to be, to be effective for the intended resultand to manage structure variations, when the substrate has surfacevariations or irregularities. Issues also relate to the propensity ofcoatings, applied to vertical surfaces, to slough, sag or wash off priorto full cure or set up. Application condition issues can relate, forexample, to: weather conditions, especially if exterior application isinvolved; humidity conditions; and/or dust conditions. The logisticalissues can concern such factors as: whether specialized personnel orequipment are needed for application; potential disruption ofconstruction site processes during application; selecting and waitingfor appropriate temperature/weather/environment conditions forapplication of the coating and set up; in some instances a need fortenting the region to be coated, and even using heaters for the tentedregion; and, related logistical issues that concern construction costs,timing and delay issues.

In addition, a variety of issues can relate to the carrier fluid for thecoating. That is, the coatings are typically applied from suspension orsolution, i.e. in the form of flowable liquid. Organic solvents orcarriers can create health and/or environmental issues: duringapplication and carrier fluid evaporation; and/or during formulation,handling and storage. Aqueous carriers can raise issues with respect tomaintaining composition integrity during handling, storage, andapplication; and, greater sensitivity to: environment conditions such asweather (temperature and/or humidity) during application and waterevaporation (drying).

As a practical commercial matter, compositions and techniques developedfor coatings that are formulated for application to constructionmaterials and surfaces, need to be developed to manage wide variationsin the above variables. Indeed, in formulating compositions forapplication, for example at construction sites, such variables as:substrate material type; substrate surface orientation;interior/exterior applications; and, any temperature/humidityvariations; etc, are preferably managed so that a selected coatingcomposition is satisfactory for as wide a variety of situations posed bythese variables, as reasonable. That is, it is not, as a practicalmatter, desirable to need to specifically formulate a composition thatis dependent on too many of the above variables in the field. Rather, itis desirable to provide a minimal number of coating compositions thatare applicable to a wide variety of substrates under a wide variety ofcircumstances, for effective practical commercial application.

In addition, it is desirable to formulate coatings that do not requirespecial, difficult to manage, handling application techniques in thefield, to the extent reasonable, so they can be applied by a widevariety of application personnel without highly developed, specialized,knowledge. That is, a commercial composition that is intended to besuccessful, for wide and extensive use, is preferably one for whichspecial on-site supervision during handling and application is notrequired, but rather which is formulated to be appropriate for effectiveapplication by personnel with a limited amount of necessary background,training and supervision.

Coating formation in thick film applications, when needed and intended,has raised significant issue in the context of coatings for constructionmaterials and similar applications. Especially when applied as a thickwet film, film distortion and integrity loss can occur with resultingblistering, puckering and/or other flaw formation during cure or filmset up. Also sagging and sloughing can affect resulting dry filmintegrity further, and with thick films initial adherence issues can beexaggerated. These variables are preferably managed by the formulator ofthe composition, so that in field applications undesired levels ofproblems are avoided.

In addition, cost factors are of significant concern. It is desirablethat the formulation be developed with materials such that compositioncosts and application costs are not unacceptable burdens for theconstruction projects involved. Also, variations in constructionspecification and regulation issues need to be met in a variety ofjurisdictions for a variety of projects, by a commercial composition,for it to be effective. Thus, the materials used are preferablymaterials of known property and characteristic, so that extensiveenvironmental and health evaluations are not required for the product tobe accepted.

These and other issues are of concern, when developing compositions forwide construction and construction material application, and are takeninto consideration by such companies as Protective Coatings Technology,Inc. of Menomonie, Wis., 54751 (now part of Polyguard Products Inc, ofEnnis, Tex., a provider of such products). The present applicationprovides compositions, composition formation techniques and methods ofpractical application to address the issues identified above, on auseful, commercially practical, scale. It is noted that the techniquescan also be applied in a wide variety of alternate applications notnecessarily involving construction sites and materials.

SUMMARY

According to the present disclosure, compositions and techniques forapplying water-borne coating compositions to substrates are described.In certain selected and preferred applications, the techniques generallyinvolve applying (with intimate mixing, typically during or immediatelyprior to applying) two compositions: (1) water-borne film-formingcomposition (Side A); and, (2) desiccant composition (Side B). Thedesiccant composition is introduced into the water-borne film-formingcomposition, to absorb free water as the application is applied, andduring film set up or cure. This means that the applicator does not relysolely on free water evaporation from the film to the atmosphere for setup of the film. Rather, the desiccant captures free water and remainsembedded in the film, after film formation.

Herein, formulation principles and techniques for the desiccantcomposition are described. Such compositions can be used with a widevariety of water-borne film-forming compositions, during application tosubstrates. Techniques usable, for example, to provide wet (and oftenthick) films on substrates, in the field, are described. Thus, thetechniques are well developed for use in the field of constructioncoatings, for example on walls and other building surfaces and/or atjoints.

The techniques can be applied in a wide of variety of applications andwith a wide variety of substrates. The techniques can be applied with avariety of polymer compositions, and generally relate to absorption offree water to facilitate set up of the film or coating, as opposed tothe film polymer composition.

Techniques of application, and resulting substrates are described.Useful coating compositions are described. Example two-part, ortwo-component, sets or systems are also described, usable to providepreferred coatings on substrates.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a step of applying a coatingformed from a two-part coating compositions in accord with the presentdisclosure, to a vertical construction surface.

DETAILED DESCRIPTION I. Water-Borne Film-Forming Compositions; ThickFilm Issues

A. Water-Borne Films or Coatings for Construction Substrates—Generally

It is often preferable that, where possible, construction films andcoatings be applied as water-borne film-forming or coating compositions.Reasons for this relate to the fact that, in general, water-bornecompositions provide less issue with respect to environmental, healthand safety concerns, during formulation, storage, handling and drying;and, often, lower costs. Water-borne coatings are well known andunderstood, and many are generally referenced as “latex coatings” and/or“sols.”

In general, with a water-borne film-forming or coating composition,polymer particles are suspended in a water or aqueous-based carrier.Once applied, film set up or cure occurs as the water evaporates to theatmosphere. Indeed, it is evaporation of (or loss of) the water thatbrings about close packing of the polymer particles, leading eventuallyto coalescing or fusion of the film. Herein, coalescing and fusion ofthe film will sometimes be referred to as “set up” or by similar terms.It may also be referred to as “cure”, although by that term, as usedherein, it is not necessarily meant that any chemical reaction occurs.

Even under ideal drying conditions in the field, latex coatings can takea relatively long time to set up and cure (several hours or more).During this time, they are especially susceptible to damage, for exampleby being washed off or otherwise damaged.

In spite of the strong preference for water-borne coatings, in manycommercial applications such as those described in U.S. Pat. No.7,825,171, incorporated herein by reference, coatings are applied fromliquid, organic-based, compositions. The reasons include that: organiccarrier materials often dry more rapidly than water; and, it can be morestraightforward to maintain the components of an organic coating insuspension/solution, in an organic solvent or carrier.

Again, a variety of problems are related to conditions of dryingwater-borne (e.g. latex or sol) coating compositions. Besides the issuesof settling during storage, there are practical issues relating to thecomposition application. These, again, include that relatively longdrying times can be necessary for aqueous-based coatings, and thelimited temperature/humidity conditions acceptable for application ofaqueous-based coatings. Other issues arise that relate generally to theapplication demands.

In order to ensure formation of an effective coating for constructionapplications, it is necessary to ensure that the substrate is very wellcoated with the composition, in spite of variations in the substratesurface, such as: cracks or rough surface material variations; joints;penetrations; etc. Typically, in the field, to obtain a sufficientlythick “wet” application to ensure coating in spite of surfaceirregularity, material variations, joint and penetration issues, thefilm often needs to be applied with a wet thickness of at least 5 mils,and sometimes at least 10 mils, typically at least 20 mils, usually atleast 30 mils, and in many instances at least 40 mils, with a typicalthickness being 40-60 mils, inclusive, or thicker. (1 mil=0.001 inch or0.025 mm, so for the alternatives stated: at 0.125 mm, often at least0.25 mm, typically at least 0.5 mm, usually at least 0.75 mm and in manyinstances at least 1 mm, for often 1-1.5 mm, inclusive or more). In someinstances, the thickness are 100 mils (2.5 mm) or more, for example 200mil (5 mm) or more. Such wet thick film applications exacerbate theissues and concerns, when water-borne coatings are involved.

For example, in many instances, the construction surface to which thefilm is applied is vertical (or nearly vertical) or even inverted (forexample a ceiling). A thick wet applied film may tend to distort undergravity, i.e. suffer slough or sag, lending to distortions orirregularities in the resulting film that are unacceptable. This isexacerbated by the fact that with a water-borne coating, and relativelyextended drying time, there is more opportunity for distortion, slough,sag or coating damage.

Especially with relatively thick water-borne coatings or films, the actof drying (free water evaporation) itself can also raise issues. As thewater is evaporated from the coating, the coating becomes thinner andcan distort. The water evaporation can lead to blisters, puckering orother irregularities in the coating (film), i.e. loss of coatingintegrity. This issue is exaggerated with water-borne coatings, as thecoating thickness is increased, since such films dry from the outsidein; and, trapped water needs to escape, as part of the drying or set upprocess (cure).

As indicated above, environmental conditions can also be an issue withwater-borne coatings. The extensive drying times required can mean thatlong construction stops are necessary. The wait times for the righttemperature and humidity circumstances, at construction sites, for aproper, even, drying (set up or cure) can create delay and expense.Unanticipated weather patterns (temperature, precipitation, humidity)can result in an undesired resulting coating or film, and the need formultiple coating applications.

Consider, for example, issues relating to applying an exterior coatingin a selected construction location. If the intent is to provide thecoating as a water-borne coat (film) forming composition, such as alatex, in colder regions, it may be necessary to provide a tent over theconstruction region of interest, and even provide heating to thelocation regional site, for application and drying of the coating. Withtypical water-borne film forming compositions, in which environmental(air) drying is used, it is generally recommended that the coating notbe applied unless the region being coated, and/or the environment, isabove 40° F. (4.4° C.) or thereabouts.

Indeed, it is many of these concerns that have (in part) led, in thepast, to preferences (in many circumstances) for application for organiccarrier-fluid coating types, see for example U.S. Pat. No. 7,825,171.

B. A General Approach to Practical (in Some Instances Thick) FilmWater-Borne Film or Coating Formulation and Application—DesiccantInclusion in the Applied Film.

In accord with the present disclosure, techniques are provided forfacilitating application of water-borne coating compositions to formcoatings or films on a wide variety of substrates, for example, onconstruction materials and/or at construction sites. This generallyinvolves providing, in the coating or film as applied, a drying agent ordesiccant that absorbs (attracts or captures) at least a portion of freewater within the film, reducing set up time, i.e. accelerating filmformation, set up or cure. When a desiccant or drying agent is includedin the film as applied, the carrier (free) water does not need to dryonly through evaporation to the atmosphere. Rather, the drying agent ordesiccant absorbs (attracts or captures) the water, and remains engulfedin the film once set up (cured). Alternately stated, the water does notneed to leave the film for film set up to occur. Rather, once itmigrates to the desiccant and is absorbed (captured), the result is aneffectively “dry” (i.e. set up or cured) film.

With respect to the above mode of operation, it is not meant to beindicated whether the water, over the long term, remains captured by thedesiccant. Indeed, in some instances after film set up, formation orcure, water may slowly migrate out of desiccant and evaporate to theatmosphere. However, this will generally occur after the film set up orcure.

Herein, the term “desiccant” and “drying agent” are used interchangeablyand are meant to refer to any material capable of taking up free waterand holding it (i.e. capturing free water). The term “absorb” andvariants thereof, are not meant to indicate any specific mechanism offree water take-up, attraction or capture, for example whether throughadsorption, absorption at reaction, and are meant to be inclusive ofeach, and any variant thereof. All that is meant by “absorb” herein isthat water is taken up (attracted or captured) by the desiccant ordrying agent in a manner that results in a enhancement to set up or cureof the coating, film, membrane or barrier.

It is noted that in some fields, a desiccant may be referenced as“active” or “inactive.” The term “active” in this context is meant torefer to desiccant that has not been fully loaded with water. Of course,an “active desiccant” can also be merely “partly active” if it alreadyhas some moisture absorbed therein, but is still capable of absorbingmore. Herein, it is intended that the desiccant be active (i.e. at leastpartly active), when the composition is applied, so that it is capableof absorbing free water in the composition.

Typically, the desiccant is of the type which attracts and holds thewater, but does not generate any reaction product with the water thatseeks to escape the system. For example, typically the desiccant is onethat does not generate a volatile product when contacted by the water.

There are additional advantages with respect to the film integrity andformation from such an approach. For example, the film does not merelydry from the outer surface in, when the desiccant or drying agent isused as described herein, in contrast to water-borne films that areapplied with free water removed only by water evaporation to theatmosphere. This means there will be less film distortion or filmintegrity loss, due to evaporation and/or the time of evaporation. Italso means that substantial amounts of free water will not be trappedunderneath outer portions of the film and against the substrate, as thefilm forms.

It is important to note, however, that, in general, the active desiccantcannot, as a practical matter, merely be applied to the water-bornecoating composition by the formulator significantly prior toapplication. Reasons for this relate to the fact that the activedesiccant, if merely incorporated in the coating composition, withoutsome modification, will immediately cause the coating composition tobegin to substantially thicken. Thus, if the active desiccant was merelymixed with the coating composition in a storage container prior toapplication, the coating composition could no longer be sufficientlyfluid for application. If merely mixed in a container, in the field,prior to application, similar problems could result, especially when thedesiccant or drying agent is selected to absorb free water rapidly,which is preferred (especially for thick film applications) so thatdrying occurs as rapidly as reasonable.

Therefore, certain preferred applications of techniques according to thepresent invention relate to adding, preferably with intimate mixing, thedesiccant to the coating composition during, or immediately before, filmapplication. It also means that immediately upon application, rapiddrying of the composition and setting up of the film occurs.

Techniques to accomplish this are discussed further herein below. Here,this point is merely meant to be an indication that the techniques andcompositions described can be formulated for an application approach inwhich a film forming composition and desiccant or desiccant compositionare separately formulated and stored, are kept separate in field, butcan be formulated to be brought together (typically simultaneously andcontinuously) during application.

With many of techniques described, it has been practical to include thedesiccant in a carrier fluid that is compatible with the water borne andfilm forming composition, but which is such that it allows the desiccantto remain dry (i.e. avoiding water exposure) in storage. This isdiscussed further below.

In general, regardless of the particular water-borne coating (latex orsol) involved, the amount of desiccant or drying agent chosen willgenerally be at least a “minimal effective amount.” By the term “minimaleffective amount”, and variants thereof, in this context, it is meantthat as applied, the film includes sufficient (active) drying agent ordesiccant therein, to absorb enough water to provide for beneficialeffect. Typically, the capacity for the desiccant to absorb free waterwill be a known to the formulator. The formulator can then ensure thatsufficient desiccant is present, to absorb an amount of free waterunderstood to be desirable with respect to the amount contained in thewater-borne coating composition. Typically, for a construction surfacecoating, an amount of desiccant capable of absorbing at least 30%, forexample at least 50% of the free water, usually at least 75% of the freewater, often at least 90% of the free water and sometimes preferably atleast 95% of the free water, will be used. In some instances, it may bedesirable to have the desiccant present in an amount adequate to absorb100% of the free water, and it may even in some instances be desirableto provide a slight excess of desiccant, to manage any issues relatingto extra water that may enter the film environment, for example from theambient environment. However, with some polymers it may be desirable toleave a small amount of interstitial water in the polymer, to facilitatefilm formation or set up, after application. When this is the case, itmay desirable to use an amount of desiccant that that leaves the amountof free water in slight excess.

In some instances, for example with alternate applications of techniquesaccording to the present disclosure to materials other than constructionsurfaces, coatings may be involved for which it is desired to onlyabsorb less than all or most of the free water present, generally tominimize drying issues but without introducing too much of the desiccantinto the composition, for desired film properties. Here the desiccantmay be introduced at a level to absorb relatively low amounts of thefree water, for example, at least, often at least 10%, typically atleast 20%, in many instances at least 30% (as an example, 30%-50%) ifdesired.

Desiccant choice will typically be a matter of preference based on otherfactors than merely ability to absorb and retain water, once thischaracteristic is present. For example, desiccant choice may relate to:ability to disperse in a composition without settling; cost andavailability; adhesion promotion capability; and transparency issues.

An example a desiccant or drying agent usable in compositions accordingto the present disclosure is Portland cement. Portland cement primarilycomprises calcium silicates; i.e. CaO.SiO₂, for example 3CaO.SiO₂ and2CaO.SiO₂. The ratio of CaO to SiO₂ is typically not less than 2.0.Other materials are typically present, in minor amounts, for examplecalcium sulfate and magnesium oxide. Portland cement is an example of an“inorganic” desiccant. While there is no specific requirement that thedesiccant be inorganic, i.e. not contain materials with carbon-carbonbonds, many usable desiccants will meet this definition.

Herein, mere reference to Portland cement, is meant to be a reference toordinary Portland cement (OPC). By this, it is not meant that thedesiccant cannot be a modified Portland cement, merely that ordinarynon-modified Portland cement is usable.

Portland cement is typically capable of absorbing up to five times (5×)its weight in free water, very rapidly. Further, it can act as anadhesion promoter, with respect to various construction substrates, forexample metal. Also, it does not generally interfere with filmproperties, and can act as a filler within the resulting polymeric film.Further, it is widely available at convenient cost. A wide variety ofdesiccants or drying agents can be used, however, examples including,but not limited to: calcium oxide; phosphorous pentoxide; aluminumphosphate; aerogel(s); glycerin; perlite; vermiculite; attapulgiteclay(s); calcium sulfate (plaster of Paris), polyacrylate acid salts(for example sodium salts) and/or bentonite clays. Mixtures ofdesiccants can be used.

C. Desiccant Composition Formation

Many desirable desiccants, for example such as Portland cement orcalcium oxide, are obtained in fine particulate (fine particle orpowder) form. In many instances, it will be desirable to suspend thedesiccant in a carrier fluid, in order to rapidly distribute it with thefilm-forming composition. However, the desiccant composition can beprovided in a solid or liquid form, depending on whether the desiccantis added to the film-forming composition as a solid, or as a materialdispersed in a liquid carrier. Typically, when a liquid carrier is usedfor the desiccant, the liquid carrier is chosen from non-aqueousmaterials that are either water miscible or water-soluble.

In accord with techniques described herein, in a typical applicationincluding mixing the desiccant with the film-forming composition duringor immediately before application, the desiccant composition isformulated separately from, and is stored separately from, thewater-borne film coating composition. The two compositions are typicallybrought together with intimate and continuous mixing, during actualapplication of the coating to a substrate, for example at a constructionsite in the field. A typical approach would be spray coating acomposition, during which, within spraying equipment and simultaneouslywith the spraying, the two compositions are intimately and continuouslymixed. Thus, by the phrase “mixing during application” and variantsthereof as used herein, reference is generally meant to a mixing of thecomposition continuously with application, and not substantially beforeapplication.

Alternately stated, it is preferred that, when the compositions arespecifically formulated for application as described herein, there be nosubstantial volume of mixed composition that stays stagnant, prior toapplication. A reason for this is that desiccant effect is often toofast for this approach to be practical.

It will typically be desirable that the film-forming composition anddesiccant composition be mixed as continuous flowing streams, when theapplication is occurring. Preferably, the time after mixing, untilapplication on the substrate, is less than a minute, usually less than30 seconds, in many instances less than 10 seconds, and it isanticipated it will preferably be no more than 5 seconds in someapplications of the techniques described herein.

In general, the desiccant composition, then, is often formulated toinclude the desiccant well suspended in a non-aqueous, fluid,environment. It is typically selected so that the amount of desiccantwhich is distributed in the film, is adequate to absorb the desiredamount of free water in the water-borne coating, to facilitate film setup in a preferred manner. Typically, then, formulation is based on suchfactors as: the amount of desiccant necessary, per unit volume or weightof water-borne coating composition, to achieve the desired set up; and,the volume of carrier fluid (if used) necessary to get the desiccantwell distributed without undesirable levels of settling; and, with avolume-to-volume ratio appropriate for applying the desiccantcomposition and water-borne coating composition to the substrate,together, during application.

Typically, the carrier fluid chosen for the desiccant, when thedesiccant is suspended in a carrier fluid, is non-aqueous, so that theability of the desiccant to absorb water from the water-borne filmforming composition is not reduced and so that undesirable water is notadded by the desiccant composition. Similarly, preferably the carrierfluid for the desiccant composition, when used, is one that is not veryhygroscopic, i.e. does not readily absorb water, so that during storageand handling water is not absorbed into the desiccant at a rate thatwould undesirably effect (deactivate) the desiccant.

Typically, the carrier fluid for the desiccant composition is soluble inwater (or at least is water miscible) to facilitate mixing when the twosides are brought together. That is, preferably the carrier fluid is nota material that tends to form a separate phase when brought into contactwith water.

In many typical applications, the desiccant is provided in a finelygranulated or powdered form, and is mixed into a carrier fluid that hasdesirable properties for intimate mixing with the water-borne coatingcomposition during application. In typical such applications, thecarrier fluid selected for the desiccant or drying agent can becoalescing solvent for the polymer system involved. Indeed, in someinstances choosing coalescing solvent for the desiccant composition canallow a formulation of the water-borne film-forming composition (Side A)with less coalescing solvent therein, than would otherwise has beentypical. In general, the term “coalescing solvent” as used herein inthis context, is meant to be used in its general sense in thewater-borne film-forming (latex) coating industry to refer to materialsthat provide one or more of the following: reduction in the totalsurface energy of the system by reducing polymer surface area; increasein capillary forces by controlling of evaporation of water; reduction inrepulsive forces between polymeric particles; and, facilitation ofdeformation of particles in contact with each other by effectivelylowering the T_(g) of the polymer. Typically, the coalescing solvent,for polymer formulations of the type used for film formation onconstruction substrates, will be non-aqueous material(s) often highmolecular weight ester(s) or ester alcohol(s). A wide variety ofcoalescing solvents that are commercially available for water-bornepolymer coating, can be used as the carrier fluid in the desiccantcomposition of the present disclosure. A specific example of suchmaterial is Texanol, an ester alcohol available from Eastman Chemical.The coating solvent can be selected for low or zero voc. For example,Oxi-Cure 1000, available from Cargill Inc, of Minneapolis, Minn. 55440,can be used. Another usable coalescing solvent type is Hexasol solvents(glycol ethers), available from Arkema Inc., Philadelphia, Pa. 19103.Yet another usable carrier solvent is NMP, i.e. n-methylpropylene(available from BASF). Also, PNP's (glycol ethers) can be used. Mixturesare usable. An example is a mixture of NMP and PNP. For example, atabout 40/60 to 60/40 (typically about 50/50) by volume.

Additional (adjuvents) may be included in the desiccant composition. Forexample, emulsifier or dispersant, to facilitate dispersion of thedesiccant or dying agent, can be used. An example of such emulsifier ordispersant is Lica 38, a organic titanate coupling agent. A useablecommercially available titanate coupling agent is available from BIOtechProducts, LLC of Randolph, N.J. 07869, as BIOchem C-3 PR65. Thismaterial comprises a mixture of an organic titanate, an organic amideand a hydrated amorphous silica. Another useful emulsifier is Bykumen,available from ByK.

In more general terms, a dispersion agent is a material that operates todisperse the powder of the desiccant or drying agent in the liquidcomposition. It can be characterized as a surfactant, typicallyoperating as an anionic dispersant when used in typical applicationsaccording to the present disclosure.

A typical desiccant composition can be formed by adding the dispersant(emulsifier) to the solvent, with mixing in a high speed disperser. Thedrying agent or desiccant (cement) can then be added, again with highspeed dispersion.

Suspending agents can be included to help maintain the cement(desiccant) in dispersion. Example suspending agents include variousclays, for example, attapulgite clay(s). A usable clay is Garamite 1958,an attapulgite clay available from Southern Clay Products, Inc., aRockwood Specialties, Inc. Company, Princeton, N.J. 08540.

In more general terms, the suspending agent is an agent or mixture thatoperates as a stabilizer or thickening agent. That is, it creates anincrease in viscosity or apparent viscosity, to facilitate inhibition ofsettling, of the desiccant or drying agent.

In some instances, it may be desirable to include extender pigments suchas ceramic microspheres.

It is also desirable to include in the desiccant composition, a carriersolvent or compatibilizer that will facilitate suspension of theparticulates in the side B non-aqueous solvent, while at the same timefacilitate good mixing with the side A aqueous composition. Suchcomponents operating as a carrier solvent in the side B will typicallybe chosen from materials that are also water soluble. Examples includenon-ionic hydroxyl propyl cellulose ether(s), such as Klucel M,available from Kremer Pigments, Inc., Gonzalez, Tex.

The amount of drying agent or desiccant included, per volume, in thedesiccant composition will be chosen based, in part, upon the volumeratio of the application technique involved, of the aqueous-basedcoating composition (A side) to the desiccant composition (B side).Typically, for techniques described herein below, the volume ratio Aside to B side will be at least 1:1, usually at least than 2:1,sometimes at least 3:1, and most often within the range of 2:1-12:1. Inmany practical systems it will be within the range 2:1-8:1, inclusive.

By knowing the volume ratio of the composition (A side and B side) forthe application technique involved, and by understanding the amount ofwater in the water-borne composition (A side) to be absorbed orcaptured, and also by understanding the water-absorbing characteristicof the desiccant (for example, Portland cement can absorb about fivetimes its weight in water), one can readily determine the amount ofdesiccant that needs to be intimately dispersed in a selected volume ofcarrier fluid for the desiccant composition.

As a practical matter, it is desirable to use as little desiccantcomposition (by volume) as reasonably appropriate and as necessary forthe intended application. Reasons for this not only relate to advantagesin storage, shipping, handling and costs, but also concern practicalapplication issues. The coating intent is to obtain a sufficient amountof water-borne polymer composition per unit of area on the substratebeing coated. The less volume in the applied wet coating taken up bydesiccant composition and application, the easier and more effective theoverall coating process can be in many instances.

With a material such as portland cement used in the desiccant, a reasonit is typically preferred that the volume ratio of Side A to Side B beat least 1:1 or greater, is that at about 1:1, the desiccant compositionwill typically only comprise no more than about 10%, typically no morethan about 5%, by weight of total composition, desiccant. At such arelatively low concentration of desiccant, not only is the excesssolvent present wasted, but formulating in a manner that comprises astable dispersion can be difficult. At a volume ratio Side A:Side B ofgreater than about 12:1, the desiccant composition could include aconcentration of portland cement of about 70% by weight, of totalcomposition. Such a composition will be difficult to formulate, and maybe at the end of acceptable viscosity for typical mixing an applicationtechniques. Of course, in making these observations, assumptions weremade about the amount of water in the Side A (coating) formulation.However, the assumptions were based on typical water-borne coatingcompositions. Again, it is expected that usually the ratio of Side A toSide B will be at least 1:1 and usually in the range of 2:1 to 8:1.

II. The Water-Borne Film or Coating Composition (Side A)

The water-borne film (or coating) composition, used as Side A, can, forexample, be a latex or sol, comprising a suspended organic compositionhaving desirable properties for the intended application. The term“latex” and variants thereof, as used herein, is meant to be used in itsgeneral sense of application in the coatings and film industry. Ingeneral, a latex is a stable dispersion (emulsion) of polymer particles(sometimes referenced as micro-particles) in an aqueous medium. Suchlatexes can be made by polymerizing a monomer that has been emulsified,for example with surfactants. The term “latex” is sometimes used inreference to an organic coating, once dried, which has been depositedfrom an aqueous medium.

The term “sol”, as used herein, is also meant to have its generalmeaning of referring to colloid suspensions of particles in a liquidmedium, in particular in an aqueous medium.

The term “water-borne” as used herein, in reference to a coating orfilm, is meant to refer to a composition containing an organic or filmprecursor for deposition on a substrate, in which the carrier fluid iswater (or is primarily water) that is dried, as the film is formed,cured or set up. The term is not meant to be specific with respect tothe nature of the deposition or the nature of the included polymer. Itis not meant to be limited to either or both of latexes and sols. It ismeant to be a general term, referring to the fact that a free carrierfluid that needs to evaporated, dried or otherwise taken up, for the setup or cure of the coating or film, is primarily water.

The terms “coating”, “film”, “membrane” and variants thereof, as usedherein, are meant to be interchangeable unless otherwise specified. Theintended reference is meant to be to a film, coating, membrane, layer,etc. which is left on a substrate after deposition and set up or cure,for example as applied from a latex or sol.

In general terms, as indicated previously, water-borne film formingcompositions are generally compositions from which, once applied, freewater is taken up, with eventual coalescing or fusion of the polymerparticles to form the polymer film. Traditional approaches involvetaking up of the water by evaporation, i.e. water leaving thecomposition by evaporation to the atmosphere. With the currenttechniques, a similar process is involved, except water take up is atleast partially by desiccant that remains in the film. When a largeamount of water take up is by the desiccant, a difference in filmformation is that when evaporation is the only technique for taking upof the water free or leaving of the free water, drying or set up occursfrom the outside in. In contrast, when sufficient desiccant is present,simultaneously a water take up, through a depth of the film, occurs.

Herein, reference to film set up or cure, is meant to be general and notspecific to a mechanism involved. It is also noted that the term“film-forming composition” is not meant to indicate that there are nocomponents in the desiccant composition that relate to film formation.Again, for example, the desiccant composition can be formulated toinclude materials to help form the film, for example coalescing solventand in some instances the desiccant composition can include somefilm-forming polymer.

The term “wet film thickness” and variants thereof is meant to refer tothe average thickness of the coating or film as applied to a substrate,prior to drying of the carrier medium. The term “dry film thickness” andvariants thereof, as used herein, is meant to refer to the averagethickness of a remaining film or coating on the substrate, once dryingof any carrier media has occurred.

The term “thick film application” without further variation, when usedin reference to the wet film thickness, is meant to refer to wet filmhaving a thickness of at least 10 mils. The term “thick film” used inapplication of dry film thickness, without further variations, is meantto refer to a dry film having a thickness of at least 10 mils (0.01 inchor 0.25 mm).

As indicated above, the thick film forming or coating composition can beformulated to leave a film with a specific chosen set ofcharacteristics. For example, a vapor barrier film and/or waterprooffilm can be formed. The particular materials selected for the filmforming component of the composition, will be selected from now knownand available, or future developed, materials deemed appropriate for theintended application.

The polymer material suspended in the latex or sol will sometimes bereferenced herein as the “polymer binder resin.” The term “polymer” ismeant to include monopolymers (homopoylmers) or copolymers, or both,unless otherwise indicated.

Techniques described herein can be used to apply a wide variety ofpolymer resins, via water-borne compositions, to form coating or filmson substrates. There is not intended to be a specific limitationsuggested as to those resins that can be used.

The polymeric materials will be chosen, for the desired property of thecoating involved. Acrylic polymers may be useful when moisture passagethrough the polymer is desired or acceptable. However, when moisturebarriers are intended, and may be preferable to use SBR(styrene-butadiene rubber) or PVC (polyvinyl chloride) materials.Polymer blends can be used. For example, the term “acrylic polymer” asused herein, is not meant to indicate that the sole polymer componentsare all acrylics. Blends may be useful to provide the polymer withdesirable elongation properties, for example. Thus, blending withpolyurethane dispersions may be helpful, whether the polyurethane isaliphatic or aromatic, or a mixture of both.

Styrene and styrene-containing polymers (styrene based polymers) havebeen used in construction polymers and can be used in applicationsaccording to the present disclosure. However, styrene polymers (wherestyrene is the only component) are relatively hard, and it may bedesirable to use polymers in which styrene is used as a comonomer, forexample in SBR polymers to provide more desirable characteristics.

Usable polymers include, but are not limited to, Carboset AE-960, anacrylic emulsion available from Lubrizol, Wickliffe, Ohio, for exampleblended with Impranil DLU, a polyester-polyester polyurethane dispersionavailable from Bayer.

B. Other Possible Components/Additives (Adjuvants) for the Film FormingComposition

1. Fillers

Fillers may be included in the water-borne film-forming composition.Typical fillers include calcium carbonate, wallostonite and/ormicrospheres (for example ceramic microspheres). Any of variety offillers compatible with polymer system intended can be used.

It is noted that in many instances, the desiccant chosen will alsooperate as a filler. Thus, in formulating the water-borne film-formingcomposition, with respect to filler choice and amount, it may bedesirable to take into consideration that the mixing which will occur atapplication, will lead to desiccant incorporated as filler.

2. Other Optional Components

A wide of variety of additional adjuvents can be included in thewater-borne film-forming composition. Pigments or dyes, antioxidants, UVabsorbers or blockers, ozone blockers, plasticizers and mold inhibitorsare among the adjuvents that may be useful in some instances.

It is often desirable to include a pH adjuster in the side Acomposition, if, otherwise, the pH of the side A composition would besubstantially different from the side B composition. For example, whenthe side B composition includes Portland cement, it may tend to berelatively alkaline. It can be desirable to include a pH adjustor in theside A composition to move the pH to 9-10 to facilitate the mixing. Anexample of such pH adjuster would be an amine pH adjuster, such as AMP95 discussed below.

It may be desirable to include freeze thaw agent(s) in the side Acomposition, such as propylene glycol. Further, it can be useful ininclude as a thickener, a colloidal agent, to help prevent particulatefrom coagulating. An example such material would be a xanthan gum; forexample Optixan D, referenced below.

Herein, no specific limitation with respect to adjuvents that may beincluded in the water-borne film forming composition is meant.

C. Formation of the Water-Borne Film or Coating Composition

The water-borne film or coating composition can be formulated usingstandard techniques in the formation of such compositions. It hasalready been noted above that in some instances, with techniquesaccording to the present disclosure, when the desiccant composition isformulated to use a carrier fluid that operates as coalescing solventfor the polymer, it may desirable to include less coalescing solvent inthe water-borne film or coating composition (Side A), duringformulation. In addition, it has been pointed out that when thedesiccant or drying agent itself operates as a filler or other adjuvant,it may desirable to use less filler or adjuvant, in formulating thewater-borne film or coating composition (Side A).

In general terms, when the composition is applied to the substrate,there are film forming components or portions and non-film formingcomponents or portions. The non-film forming components or portionsinclude, for example, filler and other adjuvents within the film onceset up. Particulate material contained within the film, once applied, issometimes referred to as “pigment” and the amount of its presence isreferred to as pigment volume concentration. With polymer systems,typically pigment volume concentration versus performance data iscollected and understood. Then, as the polymer is formulated, theformulator can use such graphs to determine acceptable levels of totalpigment volume concentration within the polymer. In general, withtechniques according to the present disclosure, as the A Side isformulated, it will be taken into account that, when mixed with the BSide, there will be introduction of further pigment or pigment volume asa result of the desiccant (and any other adjuvent) inclusion.

Thus, again, in some instances it may be desirable to have a lowerpigment level in the formulated water-borne polymer composition (the ASide) due to the fact that once mixed with the B Side, other pigment (oradditive) (at least in the form of the desiccant and potentially otheradditive) will be introduced via the B side.

III. Application of the Coating or Film to a Substrate

A. General

The film is applied to the substrate, by providing a wet film (thick orthin) on the substrate and allowing the film to set up. When a2-component approach such as described herein is used, in general it isdesired that the water-borne film-forming or coating composition (SideA) be intimately and continuously mixed with the desiccant composition(Side B) as the application occurs and not substantially before, so thatabsorption of the free water by the desiccant, from the water-bornecoating composition, is not initiated until the application isoccurring. This will typically require a rapid process of intimatemixing and application.

In more general terms, the mixture resulting from merely combining thefilm-forming composition with a desiccant-containing composition(desiccant) will typically have a relatively short pot life. The term“pot life” in this instance, is meant to refer to the length of timeafter combination, until the combination can no longer be effectivelyapplied, since it has thickened too much. Typically, the pot life forsuch a mixture will be less than 30 minutes, and often less then fiveminutes. When spray coating, the pot life may be less than one minute.

Conceptually, any of a variety of techniques for film formation can beused, to apply compositions according to the present disclosure. Forexample, the techniques can comprise brush application, sprayapplication, roller application, pour application, etc. The particularapplication approach chosen, may affect the choice of mixing conditionsand/or side A or side B composition. The reason is that someapplications lend themselves to very quick application after mixing,others require a more substantial pot life. It is anticipated that sprayapplication will often be preferred, since it can be conducted with avery short time period, in some instances, and can be used to accomplishquick coating of a large substrate, for example at a construction site.Also, a spray application can be interrupted at will, with adverse potlife affects in the application equipment, materials at coating.

In many instances it will be desirable to mix and apply the film-formingcomposition and desiccant composition with continuous (stream) mixingand application. By the terms “continuous mixing” and/or “continuousstream mixing” in this context, it is meant that sources (for examplebarrels or other containers) of film-forming composition (Side A) anddesiccant composition (Side B) are kept separate, and streams from eachare fed together with continuous mixing (and eventual application). Withsuch approaches, it will often be preferred that the time period frommixing to application is no more than one minute, often no more than 30seconds. Indeed, it will be preferred that the total duration frommixing to wet film deposition on the coated substrate be no more than 10seconds, and be as low as possible, for example 5 seconds or less.

There is no specific requirement, other than management of issuesconcerning thickening and applicability, regarding the technique ofapplication. Spray application can be used, and will typically bepreferred. However, in some instances, brush application, rollerapplication and/or pour application may be desired.

Equipment and techniques now known or developed in the future can beused for the intimate mixing and the application of the composition as aspray. Equipment manufacturers and/or suppliers such as CJ Spray, Inc.,Inver Grove Heights, Minn. 55076 and GRACO, Inc., Minneapolis, Minn.55413, can provide such equipment. The equipment can be enhanced ormodified for performance, depending upon the specific applicationintended. In general, what is required with 2-component applications isthat equipment be configured: to separately draw into the sprayer thetwo compositions to be applied in an appropriate volume ratio; and, tointimately mix the two compositions as the mixture is being sprayed ontoor otherwise applied to the substrate.

As an example, with such equipment, Side A and Side B would be drawn outof separate drums or tanks, each sent down a sufficiently long line andmixed near the tip of spraying head. The equipment would, for example,be configured for the desired draw ratio Side A: Side B in proportionsas generally described above.

A typical application according to the present disclosure forconstruction substrates will be application of sufficiently thick wetfilm application so that various irregularities etc. in the substratesurface are well coated. Examples of variations in constructionsubstrates surface include for example: pores, recesses or indents,penetrations and joints. Pores, for example, might be found in cast(set) concrete surfaces or in concrete block surfaces. By the term“penetration” in connection with a substrate surface, reference is meantto an actual piercing of the substrate, at the surface, for example by anail, screw, or projecting member, and the reference is meant to referto coating over or around where the penetration has occurred. The term“joint” is meant to have a broad, general reference and an example canrefer to a joint where materials intersect or join, whether that jointis covered with a previously applied sealant (for example caulk) or not.

A typical application of the present invention, to provide coating of aconstruction substrate or wall, above grade or below grade, will involvea wet film application that is at least 5 mil thick, often at least 10mil thick, typically at least 20 mil thick, usually at least 30 milthick and often at least 40 mil thick, for example 40-60 mil thick,inclusive, or even thicker.

The dry film thickness, will be the thickness that results after polymerset up and cure, for example upon take up of the free water by thedesiccant. Typically the wet film thickness is applied adequately toprovide that the resulting dry film is appropriate to provide thedesired protective or other properties intended. With typicalapplication to construction surfaces (such as above grade or below gradeexterior walls) an intended result will often be a dry film thickness ofat least 5 mil (0.125 mm) often at least 10 mil (0.25 mm), typically atleast 15 mil and often on the order of 15-30 mil (0.38-0.75 mm) orthicker. (There is no upper limit on thickness except as practical forthe application, so the thickness could be 100 mil (2.5 mm) or even 200mil (5 mm) in some instances).

As indicated above, the total amount of desiccant preferred in thecomposition can be calculated based upon the total amount of free waterto be applied, given a formulation application rate and thickness of thepolymer forming composition. There is no specific requirement that thedesiccant be used in substantial excess.

It is noted that an application of water-borne coating compositions (viasimultaneously mixing and applying a combination of a desiccant and thefilm forming composition) can provide many advantages. For example,because reliance is not made solely (or typically even substantially) onevaporative process for film formation and set up, wider temperatureranges and, in effect, lower application temperatures for theenvironment of application, than are otherwise acceptable, can beaccommodated in some instances, for example below 40° F. (4.4° C.),often below 32° F. (0° C.) and in some instances below 20° F. (−6.7°C.). Further, even relatively high humidity circumstances can beaccommodated. Also, the resulting relatively quick set up times (usuallyno more than 1 hour, typically no more than 30 minutes) and almostimmediate when sufficient desiccant is used) create substantialadvantage especially with thick film application in the field.

Attention is directed to FIG. 1, in which an example application isdepicted, schematically. At 1, there is depicted an constructionsubstrate, in the example shown a vertical wall, for coating. The wallor wall section 1, can, for example, be an above grade or below gradeexterior wall section. At 2 is depicted a application (in the examplespray) apparatus configured to receive therein two separately maintainedcompositions, via lines 5 and 6 respectively, with (in the exampleinternally of the sprayer arrangement 2) intimate continuous mixing oftwo feed streams and spraying. The spray application is shown at 10.

Lines 5 and 6 draw compositions respectively from containers 15 and 16.Container 15, in the example depicted the larger container, includestherein, the water-borne film forming composition. Container 16, in theexample depicted the smaller container, contains therein, the desiccantcomposition. For the example depicted in FIG. 1, it is assumed that thevolume ratio of Side A (water-borne coating composition) to Side B(desiccant composition) is substantially greater than 1:1 duringapplication.

As indicated above, a variety of mixing application techniques be used,now known or later developed. However, mere proportioners used to applymulti-component systems but which do not carefully control reactivecomponents are typically not adequate. First, they are generally notsufficiently precise, to allow for an application as required. Also,they often rely on a application volume ratio at or near 1:1, which isgenerally at a lower end of useful range for applications according tothe present invention, and usually are not preferred. Further, theyoften do not mix and apply sufficiently rapidly, to be desirable. Thatis, they will tend to clog as the desiccant begins to take effect.

In general, mixers or sprayers that operate with static mixers thereincan be useful. However, it is necessary to ensure complete, thorough,mixing or continuous film may not result. With a typical static mixer,two separate streams (Side A, Side B) are brought together in the mixerspray head, and are mixed with continuous streaming, as the sprayingoccurs. The intimate mixing that occurs in the spray head or equipment,combined with a rapid rate at which evacuation of the mixture from thespray head occurs, can provide for a desirable effect.

The techniques described herein can be used to apply materials, i.e.films or coatings, to a very wide variety of types of substrates andmaterials. These techniques can be applied in providing water-bornepolymer depositions on such materials as: masonry, cement, cement board,concrete (poured, cast, precast) wood, fiber board, plaster, plasterboard (gypsum board), metal, brick, paper, plastic, rubber, glass,asphalt and various foams and foam board (for example styrene,ioscyanate). For example, with respect to foams, it can be applied toStyrofoam, isocyanate foam, or isocyanate foam board coated withaluminum. The product can be treated or untreated, for example treatedor untreated wood products, plywood, oriented strand board, gypsumsheathing or board. Flashing materials can be coated, such as thosecomprising: polyethylene, polyethylene, PVC, polypropylene, polystyrene,TPO, EPDM, neoprene, synthetic or natural fabrics, stainless steel (forexample 304 or 316 stainless steel) copper, aluminum (for exampleanodized aluminum) lead flashing, Elvaloy KEE (a DuPont roofing productincluding pvc material). It can be a roof or coated roof. The substratescan be treated materials, for example having a paint coating or epoxythereon. Indeed, the techniques can be used to apply paint coatingsand/or epoxy coatings. The structure can be a metal panel and/or deck.The structure can even a “prepared soil”, i.e. a section of earth orsoil to which a coating is needed, for example, a soil section having agrid or web therein. The techniques can be applied to coatings sprayedonto piles of stored particulate material, to inhibit weather, forexample, wind, effects.

The techniques can be applied at construction locations in advantageouscircumstances, where water-borne coatings (for example, latex) werepreviously not recommended. For example, in cold temperature conditions(typically 40° F.; 4.4° C.) or below, and often at 37° F. (2.8° C.) orbelow, it is usually not recommended that latex coatings be applied,unless the construction region is tented and provided with heat. Withthe techniques described herein, it can be possible to apply water-bornecoating under ambient conditions (substantial environment) 40° F. (4.4°C.) or below and indeed under 37° F. (2.8° C.) at even lowertemperatures, without tenting and environment heat sources. Of course,there are lower limits of possible application, since the compositionmust be fluid when applied. The issue here, however, is that relativelylower temperature or higher humidity ambient conditions can be managedwith the application of compositions according to the presentdisclosure, than would be possible if mere environmental drying isrelied upon.

B. Further Regarding Application Equipment and Techniques, Especiallywith Spray Applications

Herein two general types of equipment are referenced in connection withmixing techniques for two-pot applications, especially used with sprayapplicators. The two types of equipment and techniques are impingementmixers (i.e. impingement mixing) and static mixers (i.e. static mixing).In general, impingement mixing is a method of mixing in which variousstreams are forced toward one another, typically at a relatively highvelocity to produce thorough mixing in a relatively short time. Themixing technique, then, generally involves streams being directedtogether, as opposed to using some form of mixer paddles to actually mixthe streams. Impingement mixers can be configured to mix liquid streamswithin the equipment; or, to direct the streams together for mixingoutside of the equipment.

In a static mixer (i.e. with static mixing) mixer elements generallycomprise a series of baffles or plates (paddles or other physicalstructures) that cause the streams to mix with one another inside of theequipment. As an example, a helical baffle may be included in a mixingsection of the equipment with the streams forced through the helicalmixer, to be intimately mixed.

There are three issues of concern, when selecting mixer and filmapplication equipment and techniques according to the presentdisclosure, to bring together two sides and achieve a good film coating.The three issues generally involve: obtainment of very good mixing; veryshort residence time in the mixer/applicator; and, avoidance ofequipment clogging or deposit issues.

Unless a very high degree of intimate mixing occurs, the film appliedmay be inconsistent and mottled.

In a typical composition, when the desiccant is merely suspended in aside B composition, the desiccant is immediately active to beginabsorbing water as soon as the two sides contact, even before intimatemixing occurs. Thus, the mixing needs to be conducted extremely rapidly,or the film may thicken adequately to cause application problems.

The third problem is deposition in the equipment (clogging). Inparticular, a technique should be used in which the two components donot cause undesirable levels of formation of film or deposit inside theapplication equipment, or application may be disrupted. Approaches toavoid this problem can involve mixing the components outside of theequipment (for example, with some types of impingement mixers) orthrough of a equipment that includes features for cleaning (flushing orpurging with gas or liquid) of the internal componentry after filmapplication occurs.

In the remainder of this section, discussion of experiences with varioustypes of applicators is provided, for a general understanding of issuesrelating to application techniques.

1. Application of Two Component Water-Borne Coating Using a PluralComponent Airless Sprayer.

An example of plural component airless sprayer is the Graco XB-70 pluralcomponent sprayer available from Graco, Inc. of Minneapolis, Minn. Suchequipment has ability to store A side and B side components in separatecontainers, and bring them together at a ratio, for example, of 2.5 to1.0 volume ratio in a mix manifold, and then to deliver the mixedproduct to the substrate(s) via airless pumping system, and ultimatelyto a spray-gun at pressure sufficient to atomize the liquid. Initially,evaluation of such a system when used with a static mixer, showed thatit did have the ability to deliver a rapidly curing productsubstrate(s). However, the rapid setting properties of a typical systemaccording to the present disclosure led to cleaning issues, fromdepositions in the mixer manifold, fluid lines and spray-gun assembly.Thus, while such equipment was capable of applying a desirable coating,it was less than fully desirable for efficient commercial application.

The shortcoming of using such a system can be addressed, if the mixingcan be conducted in the sprayer itself with a very short lifetime, alongwith a construction for cleaning the equipment, or if the mixing can beconducted outside of the sprayer, as the application occurs. Therequirements, led to investigation of impingement mixing, as a potentialviable alternative. That is, although static mixing techniques could beapplied to get a desirable coating, it was desired to investigateimpingement mixing and impingement mixers for application, for thereasons observed.

2. Impingement Mixing Application

Impingement mixing techniques can be applied, to alleviate some of theissues with static mixing. An issue with impingement mixers, however, isthat it is important to ensure a high quality intimate mixing forapplication of the film.

Impingement mixing apparatus can be configured for mixing of the streamsinside of the equipment, or mixing of two streams that are directedtogether immediately outside of the equipment, as the applicationoccurs. Either approach can be used in application of the techniquesaccording to the present disclosure. However, when the mixing occursinside of the equipment, it is preferred that the equipment beconfigured for flushing (purging) of the mixing chamber, to help protectagainst deposition of materials therein.

For consideration of application with impingement mixed techniques, aplural component impingement mix purge and spray gun was obtained fromGraco, Inc. of Minneapolis, Minn. The equipment is available under themark “Fusion.”

The particular equipment selected uses an air purge. That is, thechamber in which the two sides (side A and side B) are mixed isperiodically purged with air. Alternate equipment configurations can beused, in which the purging is conducted with an alternate gas, or with aliquid.

Specifically, application equipment was configured in which a GracoXB-70 plural component sprayer was fitted with a Graco Fusionimpingement mixing airless spray gun as an alternative to use a pluralcomponent spray with a static mixer.

With such equipment, the two fluid lines (side A, side B) are eachdirected by pumping, into a chamber where intimate mixing occurs, butwithout the use of a static mixer system, (i.e. without blades orpaddles to cause mixing, etc). The particular equipment chosen isconfigured so that this mixing occurs when the trigger on the gun ispulled back, at which time the two fluid streams are directed into themixing chamber and immediately outwardly from the nozzle of the gun asthe spray application. That is, the mixing occurs immediately upstreamof the nozzle. The equipment is configured so that when the trigger isreleased, direction of the two liquid streams into the mixing chamber isshut down, and a purge stream (in the example, a gas such as air) isimmediately directed through the mixing chamber and nozzle.

Application was found to be quite effective, using a formulation ascharacterized below. In example conducted, application was conducted atapplication temperatures that were near freezing (32° F. or 0° C.). Thetwo component water borne coating system described was applied toconcrete block and to densglass (gypsum panel material available fromGeorgia-Pacific) surfaces, at wet film thicknesses ranging fromapproximately 10-250 mils or greater. The concrete block surfaces werevertical. It is noted that prior to the coating application, theconcrete surfaces were observed to be coated with a thin layer of icethat was removed by flame. The blocks, however, were damp at the time ofapplication.

The application equipment was set a volume ratio of side A to side B of2.5:1.0. The surfaces appeared dry to the touch in less than an hour,and the applied film was observed to be thoroughly dried at less thanthree hours regardless of film thickness. After approximately 24 hoursit was noted that all of the applied films were thoroughly cured andfirmly attached to their respective substrates.

Side A and side B component mixtures used in the experiment were asfollows:

A. Side A (Polymer Composition)

1. Composition #1

Ingredient # RAW MAT'L LBS #/GAL GAL. 1 TAP WATER (carrier solvent)175.00 8.33 21.01 2 OPTIXAN D (thickener) 4.00 7.09 0.56 3 AMP 95 (pHadjuster/stabilizer) 0.50 7.86 0.06 4 KTPP (water softener) 1.00 7.930.13 5 BYK 151 (pigment dispersant) 4.00 9.08 0.44 6 IGEPAL CTA-639-W2.00 8.85 0.23 (wetting agent) 7 FOAMSTAR A-10 (defoamer) 2.00 7.20 0.288 TIOPREM “C” Gray 25.00 34.22 0.73 (TiO2 opacifier) 9 PROPYLENE GLYCOL23.67 8.62 2.75 (freeze/thaw agent) 10 CARBOSET AE-960 484.50 8.50 57.00(acrylic latex) 11 EXTENDOSPHERES TG 84.00 6.80 12.35 (extender pigment)12 NUOSEPT 95 (anti-microbial) 2.00 9.49 0.21 DISPERSION TOTALS 807.6795.752. Composition #2

Ingredient # RAW MATL LBS #/GAL GAL. 13 TEXANOL¹ (coalescent) 15.86 7.932.00 14 POLYPHASE 663² (mildewcide) 4.00 9.60 0.42 15 FOAMSTAR A-10(defoamer) 4.00 7.20 0.56 16 RHEOLATE 300 (anti-sag agent) 1.00 8.720.11 17 AMP 95 (pH adjuster/stabilizer) 2.80 7.86 0.36 18 TINT-AYD HC6317 0.33 10.35 0.03 (black shader) SUB TOTALS 835.66 99.223. Final Side A Composition: Composition #1 was Combined withComposition #2 and the Following was Added:

19 TAP WATER 6.48 8.33 0.78 TOTALS (wt./100 gal. in red) 842.14 100.00B. Side B (Desiccant Composition)

Ingredient LBS (100 # RAW MAT'L gal Mix) #/GAL GAL 20 NMP (carriersolvent) 273.83 8.560 31.99 21 Garamite 1958 20.00 13.333 1.50(suspending aid) 22 KLUCEL M (thickener) 3.00 7.400 0.41 23 GLYCOL ETHER164.12 7.380 22.24 PNP (carrier solvent) 24 BYKUMEN (dispersing aid)5.00 7.330 0.68 25 RED OXIDE RO-2597 5.00 40.891 0.12 (red oxidepigment) 26 LEHIGH TYPE 1 197.10 26.000 7.58 CEMENT (desiccant) 27EXTENDOSPHERES 175.00 6.800 25.74 TG (extender pigment) DISPERSIONTOTALS 843.05 90.25After the above was thoroughly mixed glycol ester PNP was added asfollows:

28 GLYCOL ETHER PNP (carrier solvent) 71.93 7.380 9.75 TOTALS 914.98100.00

The side A and side B compositions are then used as described above tocreate the coating. The above identified ingredients are as follows(except where elaboration is unnecessary):

-   Ingredient #2—A xanthan gum thickener (GAS: 11138-66-2) available    from ADM-   Ingredient #3—A primary multifunctional amine available from Agnus    (DOW).-   Ingredient #4—Potassium tri-phosphate available from Shifang Kindria    May Chemical Co, Ltd on alibaba.com-   Ingredient #5—A wetting and dispensing additive from Byk Chemical,    for example through AITANA-   Ingredient #6—Nonylphenol ethoxylate wetting agent (CAS #68412-54-4)    available from Rhodia Italia; Milano, IT.-   Ingredient #7—A defoamer available from Cognis (BASF)-   Ingredient #8—A titanium dioxide opanifier available from TOR    Minerals International, Inc.; Corpus Christi, Tex.-   Ingredient #10—an acrylic emusion available from Lubrizol,    Cleveland, Ohio 44141-3247-   Ingredient #11—Hollow ceramic microspheres available from Sphere    One, Inc. comprise seal fired fly ash bi-product and crystalline    silica.-   Ingredient #12—A preservative available from Ashland, Inc.-   Ingredient #13—Propanoic acid, 2-methy, monoester with    2,2,4-trimethyl-1.3 pentanediol available from Eastman Chemical Co.-   Ingredient #14—An aqueous dispersion fungicide available from Troy    Corp.-   Ingredient #15—A defoamer available from Cognis (BASF)-   Ingredient #16—A nonionic thickener available from SpecialChem-   Ingredient #18—A colorant available from SpecialChem-   Ingredient #20—N-methylpyrrolidone available from BASF-   Ingredient #21—A mixed mineral thickening agent available from    Southern Clay Products (Rockwood Specialties), Gonzalez, Tex. 78629-   Ingredient #22—A hydroxypropyl cellulose thickener available from    Kremer Pigments, Inc., NY, N.Y. 1001-   Ingredient #23—A solvent available from Dow Chemical Co.-   Ingredient #24—A high molecular weight wetting and dispensing    additive available from BYK (Altana Corp)-   Ingredient #25—An iron oxide pigment available from Elements    Pigments, Inc., East St. Louis, Ill. 62204-   Ingredient #26—A low akali Portland cement-   Ingredient #27—Identified above

IV. Additional Comments Regarding Formulation of Side A and Side B

A. pH Adjustment

In development of side A and side B components, for application inaccord with the principles, techniques and methods described herein, itis advantageous to ensure that the side A and side B components aresufficiently compatible, so that rapid, efficient, mixing will occur,under the application conditions. To facilitate mixing, it is desirablethat the pH of the two compositions be relatively similar. That is, themore different the pH, the less effectively mixing will occur under theconditions of application.

When the desiccant chosen is a Portland cement, even with a relativelylow alkaline Portland cement, pH of the side B will tend towardalkaline. To facilitate the mixing, the side A component is generallyadjusted in pH to be similar that of the side B. In the exampledescribed above, the side A composition was provided with a pH adjustor.Typically, an amine adjustor can be used, for example in the form of amulti-functional amine (as an example AMP 95). This generally was usedin an amount sufficient to adjust the pH of the overall side Acomposition to be more alkaline, typically to about 9-10, to facilitatecombining.

B. Protective Colloids

Also, in general, water-borne coating systems that are based on emulsionpolymers comprise a dispersion of resin (latex polymer) and pigmentparticles in an aqueous medium. In order to produce storage stableproducts based on these components, is preferred to keep the particlesapart from one another and suspended in the aqueous medium. Additivesthat provide this function are generally referenced as “protectivecolloids.” There are typically themselves water soluble polymers ofvariant molecular weight that hold particular matter in suspension andprevent them from premature coagulation by increasing the viscosity(i.e. thickening) the aqueous phase of the coating system. They alsohelp control and maintain the rheological properties of the coatingsystem, through the application process. An example of a water-solublepolymer that provides these benefits to the A side described above, isxanthan gum (in the example Optixan D).

The side B component of the two component coating system describedabove, also comprises a dispersion of particulate matter in a carriersolvent, and has suspension, stabilization and rheological requirementsthat are similar to the A side component. However, the B side dispersingmedia is an organic solvent, so a water soluble polymer such as xanthangum cannot be used as a protective colloid for this type of system.Ideally, a protective colloid for the B side component would be apolymer that is soluble in the organic solvent, but is water soluble (orat least water miscible) when combined with the A side component. Anexample of such a polymer type is non-ionic hydroxypropyl celluloseether (used as the ingredient Klucel M). It is typically soluble in oneof the B side carrier solvents (i.e. n-methyl pyrrolidone). As aprotective colloid for the B side component the Klucel M becomes watersoluble when it comes in contract with the A side components andeliminates particulates (i.e. problem coagulum) that might otherwisetend to form when the side A and side B are brought together.

In more general terms, then, in typical applications according to thepresent invention, the side A component will include a protectivecolloid and will often be adjusted in pH to render a pH similar to theside B component. Also typically, the side B component will include apolymer component that is not only soluble in the B side carrier solventbut is also soluble in water. A typical such material is non-ionichydroxyl propyl cellulose ether(s), although alternatives are possible.

C. Solids Content

Solids content can vary from 5% to 90%. A limiting factor on the highside is mechanical equipment ability to pump the resulting highviscosity materials. Typically, the solids content of the side Acomposition will be no more than about 60% by volume, preferably no morethan about 55%. Typically, the polymer composition used to form side Awill be a composition that, prior to incorporation in the formulation,was no more than about 70% high solids polymer by volume, typically nomore than 60%.

While alternatives to the above are possible, such formulations will bepreferred to accomplish the desired results intended.

D. Use of Water Soluble or Miscible Solvent in the B Side

As explained above, it is often desirable to use a water soluble orwater miscible solvent in the B side. This can provide advantage infacilitating the mixing. Typically, NMP, (n-methyl pyrollidone) PNP(glycol ether(s)) or mixtures will be used, but alternatives arepossible.

E. Techniques Relating to Management of VOC Levels

In some instances, it is desired to provide the formulation in a “lowVOC” manner, to manage formulations to regulations in various locationswhere the compositions might be used. The A side, due to the use ofwater as the solvent, produces relatively low contribution to VOC's. TheB side, however, relies on non-aqueous solvents, and thus can contributesubstantially to the VOC's. Overall VOC levels can be managed by usingthe following techniques:

-   -   1. Using an exempt solvent to the extent possible in formulating        the B side. An example would be to use film enhanced 400 from        Eastman. Some or all of the NMP or PNP (VOC contributing        materials) could be replaced with such solvents. Other useable        solvents for the B side include: Oxifilm 351 (from OXEA);        Oxi-cure 1000 and/or Oxi-cure 2000 (vegetable based esters from        Cargill), although alternatives are possible.    -   2. Of course using a relatively high volume ration of A side to        B side can also be of assistance in rendering low VOC levels.    -   3. Incorporating material that takes up volume on the B side        without adding VOC's are desirable. Examples include:        incorporating polymer (typically lower molecular weight        polymers) on the B side; and/or, using filler in the B side. An        example polymer completely soluble in the B side is a solution        acrylic such as AC-80 from Eliochem.

V. Alternate Applications of the Techniques Described Herein

The techniques described herein were developed to address issues ofapplying protective coatings to construction substrates, especially inthe field at construction sites, for example building sites or buildingrepair sites. Thus, the techniques described were developed to beapplicable with the types of compositions involved for such coatingsand, the environmental limitations and needs at the sites.

The techniques described, however, can be applied in othercircumstances, whether thick film or not, in a wide variety ofindustries and for a wide variety of purposes. For example, the coatingcan have purposes other than protection or in addition to protection.The coating can be for decoration, for example, to seal, or can be tomodify the surface characteristics of the resulting substrate.

In some industries it is desirable to dry applied films with ovens, heatlamps, IR lamps, blowers or heat applied from other sources. Especiallywith thick film applications, the problems with blistering, unevendrying and other film damage can result while evaporation of water fromthe applied film is completed. With use of techniques involving additionof a desiccant composition during application, and the very rapidinternal drying of the film that results, such problems and issues canbe alleviated. However, it is noted that the techniques according to thepresent disclosure are generally limited to application in situationsinvolving relatively rapid application techniques that can be conductedas the two compositions are mixed together.

In addition, the techniques can be applied with multi-component systemsin which the film being applied is a very thick material to seal agroove or joint, such as a caulk. For example, multi-component caulkingsystems, in which the A side is a water-borne emulsion, can be rapidlyset up with the B Side including a desiccant according to the presentdisclosure. It is noted that B Side can include a reactant for thecomposition, in addition to the desiccant. The term “film” or “coating”as used herein, is meant to include within its scope, a joint sealantsuch as a caulk.

By the terms “substrate” and other terms, as used herein without furtherspecification, it is not meant to be suggested that the application islimited in any manner with respect to the choice of substrate, purposeof the coating, thickness or thinness of the film, etc.

VI. Disclosure Added to Disclosure Corresponding to U.S. Ser. No.61/654,293 after Mar. 15, 2013

As indicated above, a variety of water-borne film forming compositionscan be used. A statement of such compositions, modified from thedisclosure of U.S. Ser. No. 61/654,293, is that such film formingcompositions can comprise: latexes/Dispersions/Emulsions/SOL(s)/and/orThermoplastic or Thermosetting Solution Polymers of: acrylic(s),acrylonitrile butadiene rubber(s) (NBR), asphalt, carboxylatedacrylonitrile butadiene rubber(s) (XNBR), butyl rubber(s) (IIR), EPDM,epoxies, epoxy acrylate(s), fluoroplastic resins, natural rubber(s),neoprene(s), paraffin, polyacrylics, polybutyl acrylate syntheticpolyisoprene rubber(s) (IR), polyethylene(s) (HDPE, LDPE, etc),polyolefin(s), polypropylene(s), polyurethane(s), polyvinyl acetates,polyvinyl chloride(s), polychloroprene rubber(s) (CR, Neoprene),polyvinyl butyral(s), polyvinylidene chloride(s), silicone acrylate(s),styrene acrylic(s), styrene butadiene rubber(s) (SBR), carboxylated SBR,Teflon, urethane acrylate(s), vinyl pyridine(s); and, mixtures, blendsor other combinations thereof.

VII. General Comments and Observations

According to an aspect of the present disclosure, a method of forming afilm on a substrate is provided. The method generally involves applyinga wet film to the substrate of: (1) water-borne film formingcomposition; and, (2) desiccant composition including an amount ofdesiccant adequate to at least partially take up (capture or absorb)free water in the water-borne film forming composition, as applied.Typically, the water-borne film forming composition and the desiccantcomposition are mixed immediately prior to, or during, application; i.e.the application technique is a two component technique. Of course, afterapplication, the film is allowed to set up (cure) on the substrate, withat least partial absorption of free water in the film by desiccantcontained in the film. In many instances, with solid desiccant, thewater becomes trapped in the crystalline structure of the desiccant, inthe initial capture.

A typical application approach will be a spray application with mixingof the two compositions occurring within the sprayer equipmentcontinuously, as the spraying occurs.

Typically, the step of applying comprises a wet film thickness of atleast 5 mils (0.125 mm) often at least 10 mils (0.25 mm), usually atleast 20 mils (0.5 mm); in many instances often at least 30 mils (0.75mm). Indeed, often the coating will be applied in a wet thickness of atleast 40 mils, for example within the range of 40-60 mils (1-1.5 mm),inclusive, or even much greater, for example at least 100 mils (2.5 mm)or even at least 200 mils (5 mm) or greater.

The substrate can comprise a variety of substrates and may include, forexample, vertical walls, although alternatives are possible. Withapplications described herein, it may be practical to even apply acoating to a ceiling or other overhead structure, since with rapiddrying, problems with dripping or film distortion can be minimized.

A wide variety of substrates can be accommodated with techniquesaccording to the present disclosure. Although many constructionsubstrates will comprise cast concrete and/or concrete block, a widevariety of other substrates such as wood, fiber board, plaster, plasterboard, metal, paper, foam, glass or plastic, asphalt (including modifiedasphalt) etc. can be accommodated. Unless otherwise stated, there is notmeant to be any specific limitation with respect to the type ofsubstrate involved.

The substrate can include more than one material, and can include jointsand/or penetrations therein.

Unless otherwise stated, there is no specific requirement that thedesiccant be present in an amount necessary to absorb any specificamount of the free water, other than a sufficient amount to provide forimprovement in the time of drying. However, often adequate desiccant iscontained within the applied film, to absorb at least 50%, often atleast 30%, typically at least 50%, often at least 75% and sometimes atleast 90% of the free water present in the applied composition; i.e. asapplied. Indeed, desiccant may be present in an amount adequate toabsorb at least 95% of the free water calculated to be in thewater-borne film forming composition, as applied. In some instancessufficient desiccant can be included to absorb 100% of the free watercalculated to be present, and indeed the desiccant can, in someapplications, even be used in excess.

In typical application, the water-borne film forming composition (SideA) and the desiccant composition (Side B) will be provided in a volumeratio (Side A to Side B) of at least 1:1, usually at least 2:1,sometimes at least 3:1, and in typical practical applications, within aratio of 2:1 to 12:1, (sometimes 2:1-8:1) inclusive. This is desirable,as it is preferable to ensure as much film forming composition isapplied to the substrate, per unit area, as is practical and desired forthe intended application.

A wide variety of desiccants can be used. Unless otherwise specified, nospecific limit on the desiccant or its nature, other than compatiblewith the materials involved, is intended. Example usable desiccantsinclude portland cement; calcium oxide; perlite; vermiculite;attapulgite clay(s); bentonite clay(s); phosphorous pentoxide; aluminumphosphate; aerogel(s); calcium sulfate (plaster of Paris) polyacrylicacid salts (for example sodium salts) and/or, glycerin. A wide varietyof additional desiccants may be used. Mixtures of desiccant(s) can beused. The desiccant choice will be primarily based on its effectivenessto absorb the amount of water involved. However, other factors mayrelate to: availability; cost; dispersability; ability to function as anadhesion promoter for the system involved; characteristics as polymerfiller; color transparency; and other, similar, factors.

Although alternatives may be possible, typically, the desiccantcomposition will comprise desiccant dispersed in a non-aqueous carrier.A variety of non-aqueous carriers can be used. Typically, it will beconvenient to select as the non-aqueous carrier, a liquid (or liquidmixture) that is water-soluble or miscible and that operates as acoalescing solvent for the polymer system of choice. Typical usablecoalescing solvents will comprise relatively high molecular weightester(s) and ester alcohol(s), or glycol ether(s).

Usable materials, in some applications for the non-aqueous carriercomprise plasticizer(s) for the polymer system of concern.

The desiccant composition typically includes a dispersion agent, i.e. apolymer capable acting as a dispersant for the desiccant involved.Typically anionic dispersant(s) (surfactant(s)) will be used.

The desiccant composition may also include a suspending or thickeningagent. A variety of such agents can be used, for example clays or lowmolecular weight polymers.

A film forming composition will generally comprise polymer resinincorporated in an aqueous carrier, for example as a latex or sol. Forconstruction substrates, a wide variety of polymers, typically having aT_(g) or glass transition temperature of about −40° C. will be desired,especially for cold climates. Acrylic polymers or copolymers, sometimesblended with other polymeric materials, can be very useful.Styrene-based, or styrene-unit containing, polymers, are well known asconstruction material coatings, and can be used in applicationsdescribed herein.

With techniques as described herein, application can occur even when thesubstrate (and surrounding ambient conditions) is relatively cold, forexample 40° F. (4.4° C.) or lower, in some instances even at 37° F.(2.8° C.) or lower

Also according to the present disclosure are provided two-partcompositions or sets for application of a protective film to asubstrate. The two-part composition set is formulated so that the twocomponents can be mixed together simultaneously with applying topractice the techniques described. The two-part composition or setgenerally comprises a water-borne film forming composition ascharacterized, and a separate desiccant composition as characterized.

Also according to the present disclosure, a desiccant composition isprovided that can be mixed with a water-borne film-forming composition,during application, to provide advantageously applied water-borne filmson substrates. The desiccant composition can be generally as described.

Also according to the present disclosure, coated substrates areprovided, generally through application of the two-part or two componentsystem as characterized above, typically via applications of thetechniques described above. The coated substrate can be a wide varietyof materials including, for example: cast concrete; concrete block;wood; fiber board; plaster; plaster board, metal, paper, foam(s), glass,plastics and even ground (earth) surfaces. There is no specific limit tothe number of, and type of, substrates which these can be applied insome form. The techniques are particularly advantageous in providing awet thick films and thick film coatings, although alternatives arepossible. Because the techniques are good for application of thick filmsto substrates, substrates having pores or irregularities, joints and/orpenetrations therein can be readily accommodated.

It is not required that all of the features and techniques characterizedherein above be applied, in order for coating, coating applications orcomponents thereof, to be provided with advantage, in accord with thepresent disclosure.

What is claimed:
 1. A system for forming a film on a substrate, thesystem comprising: a first component comprising a water-borne filmforming composition; a second component comprising a desiccant that isat least partially active, in an amount adequate to at least partiallytake up free water in the wet, water-borne, film; and animpingement-mixing spray apparatus that applies, by spray coating, thewet, water-borne, film to the substrate by mixing the first and secondcomponent streams by impingement mixing near a tip of a spray head,before application on the substrate.
 2. The system of claim 1 whereinthe two component streams are mixed outside of the impingement-mixingspray apparatus.
 3. The system of claim 1 wherein the two componentstreams are mixed inside of the impingement-mixing spray apparatus.
 4. Asystem according to claim 3 comprising a gas purging system that purgesthe impingement-mixing spray apparatus after application of the firstand second components to the substrate.
 5. A system according to claim 3comprising a liquid purging system that purges the impingement-mixingspray apparatus after application of the first and second components thesubstrate.
 6. A system according to claim 1 wherein the desiccantcomprises a carrier fluid.
 7. A system according to claim 1 wherein thedesiccant is present in at least a sufficient amount to absorb 5% offree water in the water-borne film forming composition, as applied.
 8. Asystem according to claim 1 wherein the impingement-mixing sprayapparatus mixes the water-borne film forming composition with desiccantcomposition, prior to application, in a volume ratio of at least 1:1 ofwater-borne film forming composition-to-desiccant composition.
 9. Asystem according to claim 1 wherein the desiccant is selected from:Portland cement; modified Portland cement; calcium oxide; perlite;vermiculite; attapulgite clay(s); bentonite clay(s); phosphorouspentoxide; aluminum phosphate, aerogel(s); and mixtures thereof.
 10. Asystem according to claim 1 wherein the desiccant is contained in adesiccant composition comprising desiccant dispersed in non-aqueouscarrier selected from water miscible and soluble materials.
 11. A systemaccording to claim 10 wherein the non-aqueous carrier is, at least inpart, coalescing solvent for the polymer in the aqueous-based filmforming composition.
 12. A system according to claim 1 wherein thewater-borne film forming resin composition comprises acrylic polymer.13. A system according to claim 1 wherein the water-borne film formingresin composition comprises styrene-butadiene rubber.
 14. A systemaccording to claim 1 wherein the water-borne film forming resincomposition comprises polyvinyl chloride.
 15. A system according toclaim 1 wherein the water-borne film forming resin composition comprisesof a blend of acrylic copolymer with polyurethane polymer.
 16. A systemaccording to claim 1 wherein the wet film, as applied, further includessuspending agent.
 17. A system according to claim 1 wherein the filmforming composition includes pH adjustor.
 18. A system for forming afilm on a substrate, the system comprising: a first component comprisinga water-borne film forming composition; a second component comprising adesiccant that is at least partially active, in an amount adequate to atleast partially take up free water in the wet, water-borne, film,wherein the desiccant is included in a desiccant composition comprisingdesiccant dispersed in non-aqueous carrier selected from water miscibleand water soluble materials; and a spray apparatus that applies, byspray coating, a wet, water-borne, film to the substrate by mixingstreams of the first and second components near a tip of a spray head,before application on the substrate.
 19. A system for forming a film ona substrate, the system comprising: a first component comprising awater-borne film forming composition; a second component comprising adesiccant that is at least partially active, in an amount adequate to atleast partially take up free water in the wet, water-borne, film; and aspray apparatus that applies the first and second components assimultaneous continuous streams that mix as the application occurs.